[vtk-developers] Render Overlay change

Randy Heiland heiland at ncsa.uiuc.edu
Fri Apr 12 10:56:17 EDT 2002


Lisa,

Any idea if this will fix the problem I reported earlier this week re text/Mesa
offscreen (see below)?

--Randy


On Apr 11,  4:23pm, Lisa Avila wrote:
> Subject: RE: [vtk-developers] Render Overlay change
>
> No API change. I've already made this change and checked it in. All tests
> pass (well, three fail on my system but they failed before I made the
> change) - but we have pathetically few tests that render 2D geometry.
>
> There are some behavior differences but the new behavior should be more
> desirable.
>
> Lisa
>
> At 03:10 PM 4/11/2002, Lorensen, William E (Research) wrote:
> >Will the API change?
> >
> >-----Original Message-----
> >From: Lisa Avila [mailto:lisa.avila at kitware.com]
> >Sent: Thursday, April 11, 2002 2:10 PM
> >To: vtk-developers
> >Subject: [vtk-developers] Render Overlay change
> >
> >
> >Hi,
> >
> >I am planning to make a change to the render process. Currently we have
> >three passes - RenderOpaqueGeometry, RenderTranslucentGeometry, and
> >RenderOverlay. The first two happen before the buffers are swapped in
> >double buffering, and the third happens afterwards.
> >
> >My proposal is to move the RenderOverlay pass before the buffers are
swapped.
> >
> >The reason it is after is historical - VTK used to support X and Win32
> >native rendering for text / 2D geometry, which was single buffered. This
> >support is now gone, so the need for render overlay to be after the
> >swapbuffers is also gone.
> >
> >The reason I want to make this change is I would like to change 2D
> >rendering over to using the RenderOverlay pass. This will make 2D geometry
> >render AFTER all opaque and translucent geometry. This means we will be
> >able to have, for example, translucent overlays while still seeing volume
> >rendering intermixed with opaque geometry behind it.

--------------------------
--- Forwarded mail from Berk Geveci <berk.geveci at kitware.com>

Subject: Re: [vtkusers] vtkScaledTextActor & offscreen
From: Berk Geveci <berk.geveci at kitware.com>
To: Randy Heiland <heiland at ncsa.uiuc.edu>
Cc: vtkusers <vtkusers at public.kitware.com>
Date: 09 Apr 2002 16:38:39 -0400

I can confirm (with a similar linux machine). I can't
explain why though. All the necessary offscreen code
is in Rendering/vtkXOpenGLRenderWindow.{h|cxx}. Maybe
someone who knows Mesa better can take a look at it ?

-Berk

On Tue, 2002-04-09 at 13:49, Randy Heiland wrote:
> Can someone tell me why a vtkScaledTextActor doesn't appear in a (Mesa)
> offscreen rendering (but does for onscreen)?  (VTK4.0, Mesa 4.0, RH7.2)
>
> Else, can someone confirm/deny?
>
> thanks,
> --Randy
>
> Here are simple Python & Tcl scripts:
>
> -------------------------------------
> from vtk import *
>
> ren1 = vtkRenderer()
>
> renWin = vtkRenderWindow()
> renWin.AddRenderer(ren1)
>
>
> offscreen = 1
> offscreen = 0
> if offscreen > 0:
>   renWin.SetOffScreenRendering(1)
> else:
>   iren= vtkRenderWindowInteractor()
>   iren.SetRenderWindow(renWin)
>
> text1Actor = vtkScaledTextActor()
> text1Mapper = vtkTextMapper()
> text1Actor.SetMapper(text1Mapper)
> text1Mapper.SetInput('frame=')
> #text1Mapper.SetFontSize(14)
> text1Actor.GetProperty().SetColor(1.0,1.0,1.0)
> ren1.AddActor2D(text1Actor)
>
> renWin.Render()
>
> w2if = vtkWindowToImageFilter()
> w2if.SetInput( renWin )
> pnmWriter = vtkPNMWriter()
> pnmWriter.SetInput(w2if.GetOutput())
> pnmWriter.SetFileName("img1.pnm")
> pnmWriter.Write()
>
> if offscreen == 0:
>   iren.Start()
>
> ----------------------------------------
> package require vtk
> package require vtkinteraction
>
> vtkRenderer ren1
> vtkRenderWindow renWin
>  renWin AddRenderer ren1
>
> vtkRenderWindowInteractor iren
> #iren SetRenderWindow renWin
>
> renWin SetOffScreenRendering 1
> #renWin SetOffScreenRendering 0
>
> vtkScaledTextActor text1Actor
> vtkTextMapper text1Mapper
> text1Actor SetMapper text1Mapper
> text1Mapper SetInput "this is a silly test"
> #text1Mapper SetFontSize(14)
> #[text1Actor GetProperty] SetColor(1.0,1.0,1.0)
> ren1 AddActor2D text1Actor
>
> renWin Render
>
> vtkWindowToImageFilter w2if
> w2if SetInput  renWin
> vtkPNMWriter pnmWriter
> pnmWriter SetInput [w2if GetOutput]
> pnmWriter SetFileName "img1.pnm"
> pnmWriter Write
>
>
> #iren Initialize
> #iren AddObserver UserEvent {wm deiconify .vtkInteract}
>
> # prevent the tk window from showing up then start the event loop
> #wm withdraw .
> _______________________________________________
> This is the private VTK discussion list.
> Please keep messages on-topic. Check the FAQ at:
<http://public.kitware.com/cgi-bin/vtkfaq>
> Follow this link to subscribe/unsubscribe:
> http://public.kitware.com/mailman/listinfo/vtkusers



--- End of forwarded mail from Berk Geveci <berk.geveci at kitware.com>




More information about the vtk-developers mailing list